Bright Color Coatings for Electronic Devices

Abstract

An electronic device may include conductive structures such as conductive housing structures. A high-brightness, visible-light-reflecting coating may be formed on the conductive structures. The coating may have adhesion and transition layers and an uppermost coloring layer on the adhesion and transition layers. At least the uppermost coloring layer may be deposited using a high impulse magnetron sputtering (HiPIMS) process. The uppermost coloring layer may include a TiCrN film, a TiCrCN film, a TiCN film, or a metal nitride film that contains Ti, Zr, Hf, or Cr. The coating may exhibit a high-brightness gold color.

What is claimed is: 
     
         1 . Apparatus comprising:
 a conductive substrate; and   a coating on the conductive substrate and having a color, the coating comprising:
 adhesion and transition layers, and 
 an uppermost layer on the adhesion and transition layers, wherein the uppermost layer comprises a TiCrCN film and wherein an atomic percentage of Cr atoms in the TiCrCN film is greater than or equal to 12%. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the coating has an L* value greater than 70 in a CIELAB color space, an a* value between 0 and 5 in the CIELAB color space, and a b* value between 10 and 20 in the CIELAB color space. 
     
     
         3 . The apparatus of  claim 2 , wherein the atomic percentage of Cr atoms in the TiCrCN film is less than 20%. 
     
     
         4 . The apparatus of  claim 3 , wherein an atomic percentage of Ti atoms in the TiCrCN film is less than 60%. 
     
     
         5 . The apparatus of  claim 4 , wherein the apparatus comprises a cellular telephone and the conductive substrate comprises a conductive housing wall of the cellular telephone. 
     
     
         6 . The apparatus of  claim 5 , wherein the TiCrCN film is deposited on the adhesion and transition layers using a high impulse magnetron sputtering (HiPIMS) process. 
     
     
         7 . Apparatus comprising:
 a substrate; and   a coating on the substrate, the coating comprising:
 adhesion and transition layers, and 
 an uppermost layer on the adhesion and transition layers, the uppermost layer comprising a TiCrCN film, wherein the coating has an L* value greater than 70 in a CIELAB color space, an a* value between 0 and 5 in the CIELAB color space, and a b* value between 10 and 15 in the CIELAB color space. 
   
     
     
         8 . The apparatus of  claim 7 , wherein the TiCrCN film is opaque. 
     
     
         9 . The apparatus of  claim 7 , wherein the TiCrCN film has a thickness between 0.1 and 1.0 microns. 
     
     
         10 . The apparatus of  claim 9 , wherein an atomic percentage of Cr atoms in the TiCrCN film is greater than 5% and less than 20%. 
     
     
         11 . The apparatus of  claim 10 , wherein an atomic percentage of N atoms in the TiCrCN film is between 25% and 42%. 
     
     
         12 . The apparatus of  claim 7 , wherein an atomic percentage of Cr atoms in the TiCrCN film is greater than 5% and less than 20%. 
     
     
         13 . The apparatus of  claim 12 , wherein an atomic percentage of N atoms in the TiCrCN film is greater than 25% and less than 40%. 
     
     
         14 . The apparatus of  claim 13 , wherein an atomic percentage of C atoms in the TiCrCN film is greater than 1% and less than 15%. 
     
     
         15 . The apparatus of  claim 7 , wherein the adhesion and transition layers comprise a Cr seed layer on the substrate and a CrSiN transition layer on the Cr seed layer, and wherein the TiCrCN film is on the CrSiN transition layer. 
     
     
         16 . The apparatus defined in  claim 7 , wherein the apparatus comprises a wristwatch and the substrate comprises a conductive housing wall of the wristwatch. 
     
     
         17 . The apparatus of  claim 7 , wherein the TiCrCN film is deposited on the adhesion and transition layers using a high impulse magnetron sputtering (HiPIMS) process. 
     
     
         18 . The apparatus of  claim 17 , wherein the adhesion and transition layers are deposited on the substrate using a non-HiPIMS magnetron sputtering process. 
     
     
         19 . An electronic device, comprising:
 a structure; and   a coating on the structure, the coating comprising:
 adhesion and transition layers, wherein the adhesion and transition layers comprise a Cr layer on the structure and a CrSiN layer on the Cr layer, and 
 a TiCrCN layer on the adhesion and transition layers, wherein the TiCrCN layer is an outermost layer of the coating. 
   
     
     
         20 . The electronic device of  claim 19 , wherein the coating has an L* value greater than 70 in a CIELAB color space, an a* value between 0 and 5 in the CIELAB color space, and a b* value between 10 and 15 in the CIELAB color space, and the structure comprises a conductive housing wall.